According to WHO statistics on blood safety, 80 percent of the world's population has access to 20 percent of the world's safe blood supply. However, more than 20 percent (13,000,000 units) of the world blood supply is not tested for the three major transfusion-transmissible infections: HIV, HBV and HCV. Transfusion of unsafe blood accounts for 2.3-4.7 million hepatitis C virus infections. If inexpensive, rapid, improved dipsticks with sensitivity comparable to EIA were developed for blood screening, it would greatly improve the safety of the blood supply in developing countries.The overall aim of the project is to develop a HCV dipstick assay with high sensitivity, designated as the reflex diagnostic. The test can be used in developed countries under circumstances where an immediate result is required. For the developing countries, we propose that this test be integrated into a triplex test (HBV, HIV & HCV) and used as the initial step of pre-donation screening in high prevalence countries. The associated second step is to use the HCV reflex diagnostic test in order to identify the agent responsible for the positive Triplex test result.The aim of Phase I is to clone and produce HCV antigens necessary for development of a rapid anti-HCV antibody detection in Phase II. These antigens include the serine protease helicase (NS3) and envelope glycoprotein (E2). At the end of Phase I, these HCV antigens will have been cloned, expressed and purified in milligram quantities.